Your emails were not sent, and you receive a bounce saying You have reached a limit for sending mail. This article explains what happened and why.
Why have my emails not been sent out?
When you complete a mail merge, you might notice that some of your emails were not sent.
YAMM specifies it in your spreadsheet with the EMAIL_NOT_SENT mention, under the Merge status column.
That happens because we failed to calculate your remaining quota correctly. For some reasons, YAMM detected that you had a smaller quota than it what was.
Google blocked my account after receiving the bounces. What happened?
To fight spam, prevent abuse and unusual activity, Google will temporarily disable your account if you send messages to more than 500 recipients or if you send a large number of undeliverable messages.
To avoid this situation, please respect the general rules about emailing to prevent spam issues described in this following article Tips: How to avoid being blocked by Google or spam filters
We invite you to consult this documentation for more information: 'My account has been blocked by Google'